PACEMAKERS DO MORE THAN PACE THE HEART

By Dr Edward Barin (Cardiologist)

When the first pacemaker was invented and used in man 1952, it was connected by thick wires to a battery on a trolley. Modern pacemakers are sophisticated minicomputers which can be packed into a metal box the size of a flattened walnut. When a decision is made to implant a pacemaker, usually for a slow heart rhythm, the Cardiologist will assess a number of things.
These include the number of wires required to maintain a normal rhythm, whether a third or fourth wire (lead) may be required, and whether the patient will need a defibrillator (ICD). A defibrillator delivers a shock to restore normal heart function should the patient suffer a dangerous heart rhythm such as ventricular tachycardia or ventricular fibrillation (cardiac arrest).

Certain pacemakers can be programmed to deliver rapid electrical impulses to override fast heart rhythms (tachycardia) to normalise the rhythm. If the patient has weakened heart muscle (cardiomyopathy) a type of multi-lead pacemaker (biventricular pacemaker) can restore the strength and coordination of heart contractions.

The technical name for a pacemaker is a CIED (cardiovascular implantable electronic device). This label also describes implantable devices which simply monitor the heart rhythm (loop recorder), monitor congestion due to heart failure, or deliver miniature electrical impulses to improve the strength of contraction.